Dual time option mechanical fuze



1966 J. H. POTTS, JR., ETAL 3,

DUAL TIME OPTION MECHANICAL FUZE 5 Sheets-$heet 1 Filed June 30, 1964 ml J n s w u fCT N J m N R T E O N W W E HLI A A s 3 8 m0 BY M 1966 J. H. POTTS, JR, ETAL 3,286,632

DUAL TIME OPTION MECHANICAL FUZE Filed June 30, 1964 5 Sheets-Sheet 2 FIG. 3

James H. Potts Jr.

Cecil L. Duncan INVENTORS.

BY AT TORN E Y AGENT Nov. 1966 J. H. POTTS, JR.. ETAL 3,

DUAL TIME OPTION MECHANICAL FUZE 5 Sheets-Sheet 5 Filed June 30, 1964 James H. Potts Jr. Cecil L. Duncan INVENTORS.

AGENT United States Patent 3,286,632 DUAL TIME OPTION MECHANICAL FUZE James H. Potts, In, Silver Spring, and Cecil L. Duncan, Adelphi, Md., assignors to the United States of America as represented by the Secretary of the Navy Filed June 30, 1964, Ser. No. 380,120 Claims. (Cl. 102-84) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a bomb fuze and more particularly to a dual option time selection system for an all mechanical bomb fuze.

Mechanical time bomb fuzes normally are made up of several parts rotatable with respect to each other, one of which is the fuze cap, which generally is calibrated in time increments and manually rotated to turn a timing disc lever within the fuze body, such that when the fuze time mechanism is activated, the disc is rotated by clockwork the preset period of time until stopped by the dropping of the timing disc lever into a recess provided in the periphery of the timing disc, releasing the firing pin to fire the fuze detonator. In this type of fuze the time delay is set when the delivery aircraft is on the grolund and thereafter the aircraft is flown and the bomb is released at predetermined altitudes governed by the time delay set in the fuze in order to achieve the bombing results desired. The purpose of this invention is to provide an all mechanical bomb fuze having such capability that an aircraft pilot can make an inflig'nt bomb fuze function time selection of either one of two delay times preset into the bomb fuze. This capability will enable the pilot to make a last minute change in bomb delivery tactics.

The only method of achieving such an optional pilot selection thus far utilized, has been with the electronic type fuze which requires aircraft charging gear capable of changing electrical voltage :and polarity of the voltage. The basic electronic circuit of this type of fuze is a capacitance-resistance-capacitance circuit which responds to changes in electrical voltage and polarity. There is limitation and disadvantage in this type tuze in that only mili tary aircraft equipped with charging .gear could be used for delivering the bomb, and further in that the accuracy of this type fuze is not good and time selections are very limited because the fuze cannot be set like a mechanical time fuze.

One readily apparent method of achieving optional pilot selection of time delays would be to use two individual timers, and yet another obvious solution would be to use two independent fiuzes. Either of these methods, however, would be expensive and space consuming.

The present invention overcomes all the aforedescribed disadvantages by providing a simple and reliable dual option time selection system for an all mechanical bomb fuze having only one timer and two sets of individually settable timing discs attached to the timer shaft via friction clutches, which system provides for extremely accurate time pickoif not achievable by any known existing systems.

Although the novel features which are believed to .be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its specific objects and advantages, the mode of its operation and the manner of its organization may be better understood by reference to the following detailed description taken in connection with the accompanying drawings wherein like reference numerals designate like or corresponding parts throughout the several views and in which FIG. 1 is a side elevation view of a preferred embodiment of the present invention;

FIG. 2 is an end view of the embodiment illustrated in FIG. 1 taken along line 22 thereof;

FIG. 3 is a longitudinal sectional view of the embodiment illustrated in FIG. 2 taken along line 3-3 thereof; and

FIG. 4 is a longitudinal sectional view of the embodiment illustrated in FIG. 2 taken along line 44 thereof.

Referring now to the drawings and more particularly to FIG. 1, there is shown a mechanical time fuze 10 having a body portion 11 adapted to receive a booster charge (not shown) at one end 12 thereof and having an arming impeller 13 at the other end. A starting arming wire 14 and an optional arming wire 15 are shown connected to spring-biased, pop-out pins 16 and 17, respectively, which pins will move rapidly outward upon removal of their respective arming wires.

The arming impeller 13 is normally enclosed in a protective cover which is secured to body portion 11 by a metallic flat spring band 18. Removal -of arming wire 14 during an aircraft drop allows the band to open for ejectimg the cover and subjects the impeller 13 for the first time to the air stream. When the impeller attains the proper speed a centrifwgal clutch 19, (best shown in FIG. 3) which may include "a plurality of centrifugal weights for urging a garter spring 21 radially outward and into engaging relationship with knurled member 22, turns the knurl 22, thereby turning worm 23 and the associated gear 24. The :gear 24 is fixed to a half-round shaft or cam member 25, which upon rotation thereof permits an environmental sensor or spring biased enabling pin 26 to be retracted from an original position wherein it blocks movement of an out-of-line explosive train slider member 27. At this point movement of slider 27 in channel 28 under the urging of a compressed spring 29 may still be negated by the presence of an arming pin 30 which is positioned to engage the flanged portion 31 of slider 27.

Simultaneous with the release of impeller 13, upon removal of the starting arming wire 14, as aforedescribed, spring-biased pop-out pin 16 is also released, tilting timer latch 32 to thereby unlock the timer mechanism 33. Attached to the timer shaft 34 via friction clutches 35, and rotatable therewith, are two sets of individually settable timing discs 36 and37. Also attached to the timer shaft 34 is a timing disc 38 having an offset portion 39 which engages arming pin 30. After the timer has functioned a predetermined period of time sufficient to rotate the portion 39 of disc 38 out of engagement with arming pin 30', the arming pin will withdraw from its engaging position with flange 31 of slider 27 under the force of compressed spring 40, thereby removing the second lock from the out-of-line explosive slider and allowing the slider to move the detonator41 in line with the booster and the firing pin 42. The weapon is now in the armed position.

, Referring now to FIG. 4 there is shown a firing pin release linkage generally indicated by the numeral 43 and featuring a dual option drop leaf 44 positioned on shaft 45 and biased thereon by a combination torsion and compression spring 46. Eachyset of timing discs 36 and 37 is provided with a'notched portion (not shown) for-receiving the drop leaf 44 which in turn releases a trip mechanism 47 for lever 48. A cup member 49 compresses spring 50 against a flange 51 on firing pin 42, which is held in position by the edge of a half-round shaft 52. The half-round shaft 52 is provided with a pin 63 abutting a finger 54 on the end of lever 48. When the trip 47 is actuated the lever 48 and its finger 54 are moved from contacting relationship with pin 53 on the half-round 52, permitting spring 50 acting on flange 51 to pivot the half-round and thereby release the firing p The dual option time selection for the fuze of the present invention is provided by the two sets of timing discs 36 and 37. The forward or long delay timing disc set 36 is shown in FIG. 4 supporting drop leaf 44 on the outer periphery of the two individual discs comprising the set, a fast-moving disc 36a and a slow-moving disc 36b geared thereto, for the one to rotate in multiple revolutions of the other, which provides a more precise time pickoff. This set of discs may be set externally of the fuze with a screwdriver through a system of extractable bevel gears 55, 55a, the setting being visually observed through a window 56. Each disc is notched in such a manner that the notched portions will be aligned under the drop leaf only when the preset time has expired.

The aft or short delay timing disc set 37 comprises fastmoving disc 37a and slow-moving disc 37b, settable through extractable gearing system 57, 57a, and also observable through window 56.

Initiation of the fuze booster is therefore attained for either a short or long time delay with the abovedescribed dual option time selection system merely by presetting the two sets of discs in accordance with the time delay periods desired, which then affords the pilot the option. As shown in the drawings, the fuze is set to be actuated according to the long delay timing period. In order to change the fuze so that it will be actuated in accordance with the shorter time delay period, it is only necessary to remove the optional starting wire 15, releasing pop-out pin 17 and permitting the spring-urged drop leaf 44 to move on shaft 45 to the aft of body portion 11 where it may engage the aft set of timing discs 37.

It should be readily apparent that a system for an all mechanical bomb fuze has been provided by this invention making possible the infiight selection of either of two delay times preset into the bomb fuze, thereby affording the pilot the opportunity to make a last minute change in bomb delivery tactics. Besides providing a dual option time selection system the present invention further incorporates many novel safety features. For example, since a significantly high rotational speed will be required to actuate the centrifugal clutch, the fuze cannot be armed by simply rotating the impeller even if the protective cover is removed. Moreover, the fuze contains an interrupted explosive train featuring an out-of-line explosive slider provided with two separate locking means. Thus, even if the starting arming wire were accidentally removed, releasing the timer and the arming pin, the environmental sensor or enabling pin would prevent the train from being aligned.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A dual time option mechanical fuze adapted to be connected to a booster charge, comprising,

a firing pin,

a spring-urged slider element positioned between said firing pin and said booster charge,

an enabling pin releasably engaging said slider element,

a timer mechanism,

a shaft rotatably driven by said timer,

first and second individually settable timing discs mounted in side-by-side relationship on said timer shaft and rotatable therewith,

a second shaft substantially parallel to said timer shaft,

a drop leaf positioned on said second shaft,

means for biasing said drop leaf against the periphery of said first timing disc and for urging said drop leaf longitudinally along said second shaft when said first timing disc is rotated by the timer mechanism to a predetermined position,

means for moving said enabling pin to release said slider and thereby align said firing pin and detonator,

firing pin retaining means releasably engaging said firing pin,

linkage means connecting said retaining means and said second shaft for releasing said firing pin retaining means when said second shaft is rotated by the movement of the drop leaf into said timing disc to thereby release the firing pin,

and la manually-releasable pop-out pin normally preventing longitudinal movement along the second shaft of the drop leaf,

whereby when said pop-out pin is released, the drop leaf is urged along said second shaft to a position wherein it engages the second timing disc instead of the first, thus providing an option of either of two preset time functions for the fuze.

2. The lfuze of claim 1 wherein said means for moving said enabling pin comprises an impeller,

at least one weight connected to said impeller and adapted to be moved radially outward from the axis of rotation of said impeller by centrifugal force,

a garter spring engaging said weight and adapted to be expanded thereby when said weight is urged outwardly,

and gear means positioned adjacent said garter spring and connected to said enabling pin for causing movement thereof when engaged by said expanding garter spring.

3. The fuze of claim 1 wherein said biasing means for said drop leaf is a combination compression and torsion spring.

4. A fuze according to claim 1 and further including a second spring-loaded locking pin releasably engaging said slider element,

a third timing disc on said timer shaft adjacent said second locking pin,

an offset portion on said third timing disc normally engaging said second locking pin,

whereby upon rotation of said timer shaft and said third timing disc, said offset portion Will be disengaged from said second locking pin thereby releasing said pin from engagement with said slider element.

5. In a mechanical fuze of the type adapted to be used with a booster charge, a firing pin, a detonator normally maintained in out-of-line relationship with said firing pin and said booster, environmental sensing means for aligning said firing pin and detonator, a timer mechanism, a drop leaf, a timing disc positioned on a shaft driven by said timer, firing pin retaining means releasably engaging said firing pin, and means for biasing the drop leaf against the periphery of the timing disc and for urging the drop leaf in a longitudinal direction when the timing disc has been rota-ted by the timer mechanism to a predetermined position; the improvement comprising a second individually settable timing disc positioned on said timer-driven shaft, each of said timing discs having a pair of members geared for one to rotate in multiple revolutions relative to the other, means for repositioning said drop leaf so that said drop loaf will be biased against said second timing disc, to thereby provide an option of either of two presettime functions for the fuze.

References Cited by the Examiner UNITED STATES PATENTS 2,438,438 3/1948 Hammond 102-84 X 2,808,001 10/1957 Kuller 10284 2,897,760 8/1959 Mott-Smith 10284 3,129,666 4/1964 Nabreski et al. 10284 SAMUEL FEINBERG, Primary Examiner. BENJAMIN A. BORCHELT, Examiner. G. H. GLANZMAN, Assistant Examiner. 

1. A DUAL TIME OPTION MECHANICAL FUZE ADAPTED TO BE CONNECTED TO A BOOSTER CHARGE, COMPRISING, A FIRING PIN, A SPRING-URGED SLIDER ELEMENT POSITIONED BETWEEN SAID FIRING PIN AND SAID BOOSTER CHARGE, AN ENABLING PIN RELEASABLY ENGAGING SAID SLIDER ELEMENT A TIMER MECHANISM, A SHAFT ROTATABLY DRIVEN BY SAID TIMER, FIRST AND SECOND INDIVIDUALLY SETTABLE TIMING DISC MOUNTED IN SIDE-BY-SIDE RELATIONSHIP ON SAID TIMER SHAFT AND ROTATABLE THEREWITH, A SECOND SHAFT SUBSTANTIALLY PARALLEL TO SAID TIMER SHAFT, A DROP LEAF POSITIONED ON SAID SECOND SHAFT, MEANS FOR BIASING SAID DROP LEAF AGAINST THE PERIPHERY OF SAID FIRST TIMING DISC AND FOR URGING SAID DROP LEAF LONGITUDINALLY ALONG SAID SECOND SHAFT WHEN SAID FIRST TIMING DISC IS ROTATED BY THE TIMER MECHANISM TO A PREDETERMINED POSITION, 